1. Field of the Invention
The present invention generally relates to a method and a device for dynamically adjusting a sync-on-green (SOG) signal of a video signal and, more particularly, to a method and a device capable of extracting an SOG signal from a video signal so as to dynamically adjust the SOG signal.
2. Description of the Prior Art
In recent years, with the development in video transmission technologies, a demand for better image quality and higher resolution has become stronger than ever. It has therefore attracted tremendous attention to exhibit high quality video precisely on a high resolution display.
During video transmission, a video signal often suffers from sources of interference which lead to distortion, color deviation, and even image jiggling. Generally, these undesirable problems result from incapable of precisely extracting the synchronization signal from the video signal. More specifically, the synchronization signal, often referred to as a sync-on-green (SOG) signal, is carried on the green color of the three primary colors RGB. The SOG signal is a clock signal and is hidden in the analog video signal. Therefore, it is crucial to extract the SOG signal from the analog video signal and determine the timing of the SOG signal.
Please refer to FIG. 1, which is a schematic diagram showing a conventional device for adjusting an SOG signal of a video signal in the prior art. In FIG. 1, a video signal is transmitted into a clamp circuit 110 so as to limit the voltage range and then is compared by a comparator 130 to a fixed clamp level defined by a fixed triggering level circuit 120. The prior art technology fails to dynamically adjust the SOG signal. Thus, the SOG signal cannot be extracted precisely when voltage shifting, noise and/or other sources of interference occur, which may cause serious problems.
Therefore, there is need in providing a method and a device for dynamically adjusting a SOG signal of a video signal, capable of extracting an SOG signal from a video signal so as to dynamically adjust the SOG signal and thus overcome the foregoing problems.